1. Field of the Invention
The disclosed embodiments relate to a vehicle body structure.
2. Description of Related Art
Japanese Patent Application Publication No. 2010-18087 (JP 2010-18087 A) describes a rear vehicle body portion of a vehicle. In summary, a vehicle body side wall of a vehicle body rear portion is formed by a side panel inner that forms a cabin inside wall surface, and a side panel outer that forms a vehicle body outside wall surface. Also, a lower portion of the side panel inner is a wheel arch portion that curves outward relative to a vehicle width direction. Moreover, in a vehicle side view, a reinforcement that extends in a vehicle up-down direction is arranged in the center portion of the wheel arch portion, and a closed section (a chamber) is formed by this reinforcement and a vertical wall portion of the side panel inner and the wheel arch portion. Also, a height direction intermediate portion of the reinforcement includes a reinforcing member formed in a hat shape that is open outward relative to the vehicle width direction in a vehicle back view, and is provided as a bulkhead of the reinforcement.
Meanwhile, a suspension damper support member having a vertical sectional shape that is an inverted L-shape in a vehicle back view extends between a cabin outside surface of a rear wheel housing and a cabin inside surface of the side panel inner. Further, a suspension housing gusset extends inclined between an upper surface portion of the suspension damper support member and a vertical wall portion of a side panel inner. A top portion on a non-open side of the reinforcement is spot welded to a weld flange portion formed on an upper end portion of the suspension housing gusset, with the vertical wall portion of the side panel inner interposed between the two, thus forming a three-ply structure.
All of the three members in the related art described above are steel sheet, but recently consideration is being given to rear suspension towers made of die-cast aluminum in order to reduce vehicle weight and the like.
However, when a wheel housing made of steel sheet and a rear suspension tower made of die-cast aluminum are directly joined together, durability may decrease (the life of the rear suspension tower may be shortened). That is, a pushing-up force toward a vehicle upper side from an absorber acts on the rear suspension tower when a vehicle is traveling. As a result, a pulling force toward the vehicle width direction inside acts on the rear suspension tower, and the rear suspension tower deforms as a result of this pulling force. Aluminum alloy material has a lower fatigue strength than steel material, so if metal fatigue accumulates in the rear suspension tower due to this deformation repeatedly occurring in the rear suspension tower, it may lead to earlier failure.